Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Dr Sowers,Thank you for taking our questions. With the addition of more powerful solid rocket motors, I would like to know how the acceleration profile during flight will compare to that of the Atlas V / Delta IV now. Will the acceleration be higher? Or has this been offset by other factors?

Thank you for doing this Dr. Sowers. I have a simple question: Will the stars and stripes paint scheme go on production vehicles or is it just artistic license for the renders? I think it looks gorgeous. Thanks, and I look forward to the first Vulcan launch!

ULA's press release says "In step two, the Centaur second stage will be replaced by the more powerful, innovative Advanced Cryogenic Evolved Stage (ACES), making the NGLS capability that of today’s Delta IV Heavy rocket.". Qualitatively will Vulcan with ACES match or exceed DIVH to all destinations from LEO to Saturn or will it be better for some orbits but not others? Quantitatively what's Vulcan with ACES's expected payload mass to LEO, 1500 m/s GTO, TLI, Mars, and Saturn? (Or better yet a plot of mass vs C3.)

My first question is the fuel choice for the first stage: methane. What prompted the use of methane as opposed to the more traditional kerosene?

My second question is how much payload could the first configuration of Vulcan (with Centaur as upper stage) put into orbit or even to Mars? The later part of the question relates to ULA's history with sending space probes out such as MAVEN and even Pluto-bound New Horizons. The size of such spacecraft ultimately depend on the capabilities of the rockets that launch them.

SpaceX has said their goal is to fly first stages back to the landing site and reuse them quickly -- gas and go. If SpaceX is successful in that, and continues an unbroken string of Falcon 9 launch successes, can Vulcan compete with that? Or is ULA betting the company that SpaceX will fail?

ULA surely did trades on full first stage recovery versus engine compartment midair... why is midair recovery so compelling, compared to the path SpaceX is on, which seems to offer the promise of far greater cost reductions?

Logged

"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

If ULA is planning to attempt either full stage or Engine and Avionincs package recovery, whatis the particular method that you have in mind for such recovery? Powered descent to land, Parachute to sea, or a combination of these strategies?

One question per member to ensure Dr. Sowers isn't overloaded with questions. Ensure your question is well presented, readable and worthwhile and please read the coverage of the reveal here: http://forum.nasaspaceflight.com/index.php?topic=37251.0 - to ensure you don't ask a question already addresses (or that you ensure it asked for clarification of an answer).

Before I dive into the questions, I'd like to thank Chris for giving me the opportunity to do this Q&A. As I wrote in a recent op ed (http://dpo.st/1albze6 ) developing new rockets is a good as it gets for someone in our business. It's clear that all of you share my enthusiasm. And that makes answering your questions really fun.

All best with the Vulcan. It has turned me into a ULA fan and many others judging by forum activities and name voting.

Do ULA plan to introduce IVF on Centuar or will it wait for ACES?.

Business case to close. Thanks! As Tory said in the press conference, we got well over 1.1M votes.

IVF is an integral part of the ACES design. We would like to field it on Centaur earlier, but need to find the right opportunity to get the business case to close. Without going into details, we are actively pursuing several possibilities.

Thanks very much for doing this with us. Can you talk about any timelines or capabilities for Vulcan human launch? That wasn't touched on at all during the press conference, but with CST-100/Atlas making a lot of news, I'm sure things like pad access etc are in the works.

Thank you.

It's our plan that Vulcan will be human rated. We are incorporating human requirements from the outset and involving the commercial crew office in the development process. For example, we have constrained the height of the vehicle to maintain the CST-100 interfaces at the launch site unchanged as well as the interfaces to the Centaur. How and when we transition from Atlas to Vulcan will be worked in collaboration with our Boeing customer and NASA.

If you and your rival are equally successful at your respective first stage "reuse" strategies, how well will they compete in terms of increasing overall annual launch frequency of each vendor?

Thank you again in advance for answering my humble question.

An excellent question. The answer is: it remains to be seen. Increasing launch rate means increasing launch sales which means getting new customers. That can happen in two ways: take customers away from someone else (via lower prices) or generate new demand. We all hope for the later.

The challenge for reuse has always been with the business case. Can you get the cost of recovery and refurbishment low enough to truly save money? No one has done it yet. We believe the approach outlined yesterday gives us the best shot at it.

BTW, I have a simple parametric spreadsheet that runs through the economics as a function of number of reuses, and the various relevant cost parameters. When I get some more time, I'll post it here and let you guys have fun.

My question is whether the vehicle (or a specific configuration) be rated for nuclear payloads (IE: science missions with Plutonium)?

Currently, Atlas is the only LV in the US fleet that has carried nuclear payloads (Pluto New Horizons and Curiosity). We are quite familiar with the process and expect Vulcan will eventually carry nuclear payloads. The process is done on a mission specific basis. There is no blanket nuclear certification to my knowledge.